Infinity NikkiThe challenges of the Curio area usually have some areas, but there is one very difficult challenge that can be found near the Choo-Choo station. Completing this challenge, which can be found northwest of Choo-Choo Station under one of the stone trees towering above the Abandoned District, is much easier than completing it.
To reach this Curio Domain challenge on Infinity Nikkiyou want to head northwest of the Choo-Choo station and find the Choo-Choo Stonetree Top Warp Spire station. From here you can find the Curio Domain by scrolling down and east, under the Stonetree.

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Infinity Nikki: How to Ride the Choo Choo Train
Players who received the Daily Wish that teaches them to ride the Choo-Choo train in Infinity Nikki can learn how to complete that task here.
How to solve the Domain Curio challenge near Choo-Choo station
Go to the location shown on the map above (easily reached by traveling from the Choo-Choo Stonetree Top Warp Spire Station) to find the challenge. Head inside to see the platform challenges you must overcome to win the Whimstar here.
Inside the platform you'll find a large purple block that swings up and down, and several fans to power up your Floral Gliding Outfit. To get to Whimstar, you need to time your jumps and swings to accommodate the movement of these obstacles. The first few jumps are very easy, just use the fan as the block in front of you rises to send Nikki through the gap and onto the platform past the block.
Next, you need to use the fan that points straight up to lift Nikki into the air, then wait for the block on the left to come down and run to land on it. From here you can reach another fan that will take you to the top area of the first platform you were on when you use it.
Then, you need to jump from the moving block you're on as you start going back down so you get to the block on the right as it rises and you can jump under it and onto the next platform. This is the hardest jump in this challenge and may take a few tries. See the video instructions at the top of this article for additional help if needed.
From here, go up the ramp and onto the moving block, use it to reach the top fan. This fan will allow Nikki to glide to Whimstar with the Floral Gliding outfit. Get the Whimstar to complete the challenge.